Zarr vs. COG

At the recent Cloud Native Geospatial conference in Utah (presentation recordings), Zarr was reported to be the star of the show. What is Zarr? Wait, what is COG? and what the hell are Korg and Crablante doing in the geospatial group?

Definitions

OK, Korg and Crablante are just for fun--they're just random antiheroes. COG stands for cloud-optimized GeoTIFF. COG is a GeoTIFF file that enables more efficient workflows in the cloud environment. Zarr, despite sounding like a superhero that would fight Korg and Crablante, is a newer, community-maintained format for large-scale n-dimensional data.

Uses

Jarrett Keifer and Julia Signell of Element 84 have an excellent overview asking if Zarr is the new COG. The short answer is they're different. Zarr's strength lies with 3D n-dimensional data cubes, whereas COG excels at the speedy tiling of 2D raster data in the cloud. In reality, it isn't an 'either-or' question but a 'both and'; use is dependent on what you want to do.